The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Switching power supplies contain, in addition to other components, one or more magnetic components, e.g. inductors, transformers, etc., through which a current flows and one or more switches to control the flow of current from an input power source. The switch, or switches, are turned on and off in a cycle. The ratio of on-time to off-time is the switch's duty cycle. One way the output of some power supplies is regulated is by varying the ratio of the on-time to the off-time of the switch, i.e. varying the duty cycle. The specific operation of various power supply topologies is well known and for the sake of brevity will not be further discussed herein.
There are at least three modes in which switching power supplies may be operated. In continuous conduction mode (CCM), the current through a power supply magnetic element is always higher than zero in each switching period. When a power supply operates such that the current through a magnetic element is zero for an infinitely small time in each switching period, it is said to operate in critically discontinuous conduction mode (CDCM). Finally, when operated in discontinuous conduction mode (DCM), a power supply operates such that the current through the magnetic element is zero for a measurable amount of time in each switching period.